Climate Change Mitigation Potential of Biochar:A Review and Framework for Carbon Accounting

Master’s Project presented by John SwansonAdvisor: Dr. Daniel Richter

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Outline• Prologue: Climate Change• What is Biochar?• Study Methods• Biochar Background• Biochar Project Types• The Climate Mitigation Potential of Biochar• Current Market Incentives• A Carbon Accounting Framework for Biochar• Conclusions

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Prologue: Climate Change

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• Lower atmosphere and oceans are warming

• No natural occurrences (e.g. increased solar irradiance) can account for recent changes

Prologue: Climate Change

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• Combustion of fossil fuels (coal, petroleum, natural gas) is primary cause

• Has caused increases in heat-trapping greenhouse gases (carbon dioxide, methane, nitrous oxide and some halocarbons)

• Increases radiative forcing

Prologue: Climate Change

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• Anticipated effects of climate change include changes in weather patterns, storms, drought

• Affects human habitation, agricultural systems, ecosystems and species (extinctions).

Areas of recent exceptional drought in Texas; The Brazos River is running dry.

Prologue: Climate Change

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• Polar ice and glaciers receding

• Sea levels rising

Hurricane Sandy storm surge inundating New Jersey Coastline, 2012

Marshall Islands high tide, 2011

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Prologue: Climate Change

• Policy and scientific responses: alternative energy, efficiency, carbon sequestration

Biochar

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• Biomass deliberately charred and applied to soil -- Biochar

Study Methods

• Review scientific literature on biochar• Evaluate biohcar’s potential as a climate

change mitigation tool• Analyze these characteristics in context of

existing carbon market incentive programs• Produce a recommended framework for

carbon accounting for biochar

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Biochar Background

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• Biomass has long been used for energy

• Biomass combustion is carbon neutral

• Fossil fuel combustion adds carbon to the cycle

Biochar Background

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Carbon-negative energy production, multiple benefits from biochar

Biochar Background

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• Biochar from fire is naturally occurring– 5-15% (or more) of North American prairie soil– Australia, Africa, South America

• Biochar is very stable– Natural Australian soil char 1,300-2,600 yrs old– Man-made Amazonian biochar 600-8,700 yrs old

• Far more stable than original biomass– Presence and age in existing soils– Resistance to decomposition in soil in laboratory

incubation, compared to biomass

Biochar Project Types

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• Terra Preta in the Amazon Basin– Ancient technique

– Supported vast communities

– Could be duplicated in industrialized countries or developing nations (slash-and-char vs. slash-and-burn)

Biochar Project Types

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• Modern techniques– Pyrolysis, gasification (also torrefaction, flash

carbonization, hydrothermal carbonization)

• Fast pyrolysis: 13% syngas, 75% oil, 12% char• Slow pyrolysis: 35% syngas, 30% oil, 35% char• Gasification: 85% syngas, 5% oil, 10% char

Climate Mitigation Potential of Biochar

• Studies of annual global mitigation potential– Woolf (2010): 1.8 Pg C annually (12% of

anthropogenic emissions)– International Biochar Initiative: 0.2 to 2.0 Pg C/yr– Nicholas Institute: 0.18 Pg C/yr in U.S. agriculture

• Terra Preta soil – 250 Mg/ha• Non Terra Preta soil – 100 Mg/ha• Above ground biomass – 110 Mg/ha• Productivity improvements variable and not

fully characterized15

Current Carbon Market Incentives

• Regulatory– Clean Development Mechanism (Kyoto)– European Emissions Trading Scheme– California Cap-and-Trade

• Voluntary– Verified Carbon Standard– Climate Action Reserve– American Carbon Registry

• Biochar not currently included

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Current Carbon Market Incentives

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• Protocol proposed

• Could be developed

• Would have to meet program criteria: – Additionality,

– Permanence

– Verifiability

– Ownership

– Quantification

Current Carbon Market Incentives

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• Limitations:– CA: 0.055 Pg C/yr

to 2020– EU ETS: 0.039 Pg C/yr

to 2020– Together = 5% of global

potential if all offsets were from biochar

• Other incentives: tax breaks, subsidies

• Some systems will be self-sustaining

A Carbon Accounting Framework

• Biochar seems to be a tool worth pursuing• May occur in multiple sectors to varying

extent• 4 Gasifiers in CA currently, 1 under

construction; numerous unmonitored farm-scale systems in U.S. and globally

• A framework and database for carbon accounting for projects would be desirable

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A Carbon Accounting Framework

• The amount of biochar produced over time.• Carbon content of the biochar• Labile (volatile or easily decomposed) and recalcitrant

fractions of the biochar • The disposition of the biochar after production• Information on the feedstock: composition, source,

location of origin, sustainability• Quantitative information on the disposition of the

energy produced• Lifecycle energy inputs used to produce the feedstock • Characteristics of the soil to which biochar is applied

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A Carbon Accounting Framework

• Recommended list of parameters– Char chemistry (pH, metals, dioxins, PAH, etc.)– Char physical parameters (CEC, surface area, etc.)– Char production characteristics (feedstock,

temperature, process, etc.)– Char disposition and application (location,

application rate, soil type, etc.)– Quantified soil characteristics of soil before and

after application

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Conclusions

1. Biochar must play a role in climate change mitigation

2. Biochar projects have the potential to feasibly/sustainably offset >1 Pg (1 billion tons) of CO2 carbon equivalents annually

3. Current carbon market incentives are not sufficient to rapidly increase or maximize the initiation and development of biochar projects

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Conclusions

4. Other financial incentives could be used to accelerate the implementation of new projects.

5. Incentives should be prioritized for initiation of projects with greatest mitigation or economic potential

6. Uncertainty regarding recalcitrance in soil should not inhibit efforts for project initiation and development

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Conclusions

7. Biochar projects should be pursued despite conditions that may favor biomass combustion

8. A comprehensive carbon accounting system should be developed to evaluate global impact of biochar projects on net greenhouse gas emissions and climate.

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Biochar

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